Restless and Impulsive
Frank is a drifter, both literally and emotionally. He’s not tied to a stable career or community, which reflects his inner restlessness. This restlessness makes him prone to rash decisions—most notably, plotting to murder Cora’s husband.
Psychologically, Frank is driven by immediate gratification. He often acts on desire rather than long-term reasoning, showing a tension between rational thought and instinctual drive.

Guilt and Self-Justification
After committing morally reprehensible acts, Frank experiences guilt but also rationalizes his behavior. His internal conflicts highlight Cain’s interest in human psychology: people can commit extreme acts and still maintain a sense of self-justification.

Survivor Complex
Frank displays a kind of pragmatism blended with amorality. He is often guided by survival instincts—sometimes physical, sometimes emotional—which makes him both relatable and unsettling.

The Cynical Drifter
Psychologically, Frank exhibits traits of impulsivity and a lack of long-term planning. His affair with Cora is driven by a combination of lust and a desire for excitement, rather than genuine affection. This impulsivity extends to his involvement in the murder plot against Nick, where he acts without fully considering the consequences. Frank's manipulative tendencies are evident as he uses his charm to influence those around him, including Cora and Madge Gorland.

Despite his outward confidence, Frank harbors a deep-seated insecurity and fear of commitment. His relationships are characterized by a pattern of brief encounters and a reluctance to form lasting bonds. This fear of intimacy may stem from a past filled with instability and transient relationships, contributing to his current emotional detachment.

Ambition and Desire for Control
Cora is trapped in a marriage she despises, and her ambitions for wealth and autonomy motivate her to manipulate circumstances—including Frank—to her advantage. Her psychological complexity lies in her dual nature: vulnerable yet fiercely calculating.

Erotic Power and Emotional Intensity
Cain portrays Cora as using her sexuality consciously as a form of power. Her relationship with Frank is intensely passionate, blending genuine desire with manipulation. This creates a tension between love and control that complicates her psychology.

Moral Ambiguity
Like Frank, Cora is morally ambiguous. She commits extreme acts but is portrayed sympathetically, which challenges the reader to understand rather than simply judge her. Her psychology is shaped by frustration, ambition, and a desperate desire for freedom.

The Femme Fatale
Psychologically, Cora exhibits traits of narcissism and a strong desire for control. She views her marriage to Nick as a means of survival rather than a source of emotional fulfillment. Her affair with Frank is not only a pursuit of passion but also a calculated move to gain leverage over her circumstances. Cora's willingness to conspire in the murder of her husband highlights her capacity for manipulation and moral flexibility.

Cora's actions suggest a deep-seated dissatisfaction with her life and a yearning for power and autonomy. Her behavior can be interpreted as a response to feelings of entrapment and a desire to reclaim agency over her destiny. Her manipulative tendencies and willingness to betray those close to her underscore the darker aspects of her personality.